The field of the present invention is related to optical hearing devices.
The prior methods and apparatus for providing sound to users can be less than ideal in at least some respects. People like to communicate, and hearing is an important aspect of communication for both communication devices and prosthetic devices such as hearing aids.
Contact hearing devices that contact tissue or bone have the advantage of providing sound with decreased feedback along the ear canal to the input microphone. However, the ear is composed of several small and delicate structures such as the tympanic membrane, ossicles and cochlea. Providing compact hearing devices that fit comfortably within the ear and contact moveable structures of the ear to provide high quality sound can be challenging. Transmitting power and signals to such small devices has also proven challenging.
Recently, it has been proposed to use light based hearing devices. Light based hearing devices have the advantage of potentially being small and providing high fidelity sound. However, realization of these potential advantages has proven challenging for several reasons. Sound is transmitted with positive and negative changes in air pressure. However, the light energy transmitted from a light source only results in the generation of positive light energy, with no corresponding negative light energy being available. Although light does oscillate with electrical and magnetic fields in the Terahertz frequency range, such frequencies are too fast for most detectors to capture the oscillating positive and negative field components of light. Consequently prior methods and apparatus used to drive electrical signals associated with positive and negative sound pressure may not be well suited for use with light based systems. Also, optical components can introduce distortions to optical signals, such as non-linear behavior of the light source and detector, which can present additional challenges.
At least some of the prior electronic circuitry solutions are less than ideally suited for the transmission of light based optical signals. For example, the use of prior delta-sigma modulation with optical signals can result in more power consumption than would be ideal. Similarly, prior analog approaches to transmitting electrical signals can result in increased power consumption when used with optical systems. As hearing devices can be worn for extended amounts of time, excessive power consumption may result in less than ideal performance of the hearing device in at least some instances.
In light of the above, it would be helpful to provide improved methods and apparatus for optical hearing. Ideally such optical devices would provide decreased power consumption, low amounts of distortion, be compact, and transmit the optical signal and energy to power the transducer with decreased amounts of distortion.